A DC Blocker to help stop transformer HUM

[sergeauckland]

Hello, do we know if removing a ground from the plug to a screw on the chassis could solve this?

Greetings

Removing the ground connection will have no effect whatsoever on transformer hum, and could make the product lethal. Do not do it, at all, ever!

S.

 

[wigglerabbit]

Just personal expereince…but I had really good luck with Emotiva’s power strip. They are indeed a bit pricy, but
work very well for my Monolith 5x that had a terrible transformer hum.

 

[Anterantz]

Remove no, I say connect a cable from ground to the chassis of the arcam avr since the avr the rear connector is only two pins and does not bring ground.

 

[sergeauckland]

Remove no, I say connect a cable from ground to the chassis of the arcam avr since the avr the rear connector is only two pins and does not bring ground.

Adding a ground to a double-insulated product will not reduce transformer hum at all, but could introduce a ground loop and create hum audible on the loudspeakers.

S

 

[Anterantz]

I'm between the atl or the ifi dc blocker, the atl looks better built but if I don't notice any improvement I won't be able to return it!

The ifi I can always return it if the result is not appropriate.

I'm in doubt since it's been like a few days that I haven't
I hear nothing.

Yesterday I tried to measure with a multimeter in phase + ground and I got 248v and then I measured neutral + ground and I got 0.04 I don't know if this is the DC.

 

[ToKillTime]

I received the ifi yesterday and the hum is reduced significantly when the Blocker is plugged in.

Next I will try the one from audiolab and then I will decide which one I will keep.

 

[Anterantz]

I received the ifi yesterday and the hum is reduced significantly when the Blocker is plugged in.

Next I will try the one from audiolab and then I will decide which one I will keep.

Great help, could you see if you lose dynamics or sound quality?

 

[ToKillTime]

I could not notice any loss in audio quality so far.

 

[vco1]

Buy those products instead of cheap ones.

My amp is/was a Cambridge Audio Azur 840A. At the time a €1500 device with a lot of good reviews. Still, it was humming like crazy. Basically from day one. My el-cheapo Kenwood KA-5010 was much better in that respect.

 

[restorer-john]

My amp is/was a Cambridge Audio Azur 840A. At the time a €1500 device with a lot of good reviews. Still, it was humming like crazy. Basically from day one. My el-cheapo Kenwood KA-5010 was much better in that respect.

A pity you didn't return it there and then. It has two toroids, do they both hum or is it just one?

 

[vco1]

A pity you didn't return it there and then. It has two toroids, do they both hum or is it just one?

I did send it in. Nobody could hear a thing. As they told me, it was absolutely quiet.

It was the big toroid that hummed the most. The small one was barely noticeable. The 804C cd player also has a toroid. And the hum from that one is/was also neglectable.

 

[Colin James Wonfor]

I did send it in. Nobody could hear a thing. As they told me, it was absolutely quiet.

It was the big toroid that hummed the most. The small one was barely noticeable. The 804C cd player also has a toroid. And the hum from that one is/was also neglectable.

I have had this trouble also and on the early Claymore's in certain location i.e. industrial or large town the hum was there and now and again I get same on some of the new kit. In some cases a DC blocker works, but in others the mains is to high and then you are screwed. For the Claymore we had Airlink (pt no 916) add 20% more winding on the primary and also the secondary, Problem in most case solved.
The new odd hum on again certain areas is due I found to mains borne coms from smart meters and my heart monitor communicating data over the mains, and this works often with either a mains filter or moving kit around on a separate ring main.
The other thing I notice with our new mains cable the interference from the digital garbage also disappeared but my cable is EMC loaded. (no I am not going tell how).
The cheap iron cores saturate you can often see this on scope and by looking at the voltage out and the load current it is easy to spot. In saturation you will see a current spike and often a flat top voltage, and the two can be seen at the start and the end of the distorted voltage wave form.

Have fun stay safe best Col ( put the earth back please)

 

[Colin James Wonfor]

My amp is/was a Cambridge Audio Azur 840A. At the time a €1500 device with a lot of good reviews. Still, it was humming like crazy. Basically from day one. My el-cheapo Kenwood KA-5010 was much better in that respect.

The other trouble this amp has in a strange """ A Class""" design add on done by a famous """design Engineer """ he also put op-amps in parallel and wondered why they died, this shit design caused us at Cambridge lots of problems, I may still have the circuits I dig them out. (the design was not this illiterate twit here).

 

[Anterantz]

Yesterday the buzzing came back for a few seconds and it didn't come back anymore.

I just reviewed my entire installation, separate power cables and separate avr from any pc or amplifier that could interfere.

I just tried an ifi ac purifier that
I already know that it is not a dc blocker but I have not noticed absolutely nothing of improvement (I was already afraid of it) but out of simple curiosity I tried it.

I'm afraid the ifi dc blocker can do the same.

 

[ToKillTime]

I got the chance to test the Blocker from Audiolab and this one reduces the noise as well. Even netter than the one from ifi.

 

[Anterantz]

I'm going to ask the audiolab to test it, I hope I don't lose dynamics in the sound!

Does anyone else have it? I get about € 100 I see that it looks something better built than the ifi dc blocker although this audiolab will need a double cable to insert it and
the ifi dc blocker saves you the cable.

 

[garbz]

I hope I don't lose dynamics in the sound!

There is zero possible way grounded in physics or engineering that this could reduce dynamics in the sound. If anything the transformer not saturating due to DC may increase the PSU rails and thus headroom, but I will happily bet my kidney that it has zero improvement effect either.

Also please don't mess with your earthed chassis. They are earthed for a reason. Your earlier post about lifting the safety earth and connecting it to your AVR not only makes the amp unsafe, but the AVR as well.

Also not all transformer buzzing is due to DC. Quite often it's just a poorly made transformer, that said since you claim the buzzing varies and comes and goes then it is likely a DC issue. Is it worse during the day than at night? Is it worse with LED lights on or while the wife is blowdrying her hair?

 

[Anterantz]

There is zero possible way grounded in physics or engineering that this could reduce dynamics in the sound. If anything the transformer not saturating due to DC may increase the PSU rails and thus headroom, but I will happily bet my kidney that it has zero improvement effect either.

Also please don't mess with your earthed chassis. They are earthed for a reason. Your earlier post about lifting the safety earth and connecting it to your AVR not only makes the amp unsafe, but the AVR as well.

Also not all transformer buzzing is due to DC. Quite often it's just a poorly made transformer, that said since you claim the buzzing varies and comes and goes then it is likely a DC issue. Is it worse during the day than at night? Is it worse with LED lights on or while the wife is blowdrying her hair?

It is safe because it happens from time to time but I would not know how to tell you when it happens since it becomes very random.

It sounds a couple of seconds and disappears for days, I have lowered all the thermals in case it could influence but when I have
down I have not noticed any difference.

I also have a totally separate line from the rest of the house when I build the room.

I was going to order the audiolab but I can't return it if it doesn't help me at all, I already bought an ifi ipurifier and the
I haven't really noticed any differences in the sound.

Greetings

 

[jjk1]

I just connected one of those emotive dc line filter /offset eliminators and it actually did the trick. No more hum from my amp.
i honestly didn’t think it would work but it did. It was not much of a problem but it’s silent now.

 

[tmtomh]

I just connected one of those emotive dc line filter /offset eliminators and it actually did the trick. No more hum from my amp.
i honestly didn’t think it would work but it did. It was not much of a problem but it’s silent now.

The nice thing about DC blockers (compared to many other types of power-related devices) is they’re a pretty cut and dried, binary thing: they work on one type of issue, and generally they either work or they don’t. There’s not usually any question of a subtle, “is it real or not” sonic impact. Glad it worked in your situation!